The stage is a scuffed square in the middle of a black-painted room. Rows of chairs rise around it, bleacher-style, on all four sides. No curtains or fancy sets divide those watching the action from the action itself. This is the Vortex, Albuquerque’s highly regarded community theater now in its 36th year—and, as it happens, a fitting home for the stripped-down intimacy of Anton Chekhov’s classic drama-comedy, The Seagull.